This invention relates to a burner for the partial oxidation of liquid, carbonaceous fuel by means of steam and an oxygen-containing gas.
Burners of this kind, which are directed into a combustion chamber, are known for instance from EP 0 127 273 B1, the U.S. Pat. No. 4,933,163 and EP 0 707 880 A1. From the last-mentioned publication it is also known to dispose such burner at the entrance of an empty combustion chamber, the raw product gas produced being cleaned subsequently and being processed for instance to obtain a synthesis gas.
It is the object underlying the invention to create a burner for the partial oxidation of liquid fuels such as heavy oil, which burner is suited for high throughput capacities and at the same time allows an inexpensive operation. In accordance with the invention this is achieved in that at least two fuel-carrying tubes are arranged in parallel, the distance between adjacent, fuel-carrying tubes being 5 to 30 cm, that each fuel-carrying tube is surrounded by a steam-carrying tube, that the orifice end of each steam-carrying tube has a supply line for oxygen-containing gas, and that the steam-carrying tubes are surrounded by a common first cooling chamber through which cooling liquid is passed, the first cooling chamber constituting an annular chamber and extending into the area of the orifice ends of the steam-carrying tubes. The number of fuel-carrying tubes usually lies in the range from 2 to 20 and preferably from 3 to 12.
Due to the common first cooling chamber a compact, relatively simple construction of the burner is obtained, at the same time a sufficient cooling of the area of the orifice ends of the steam-carrying tubes is ensured, which tubes are exposed to the high temperatures in the combustion chamber. At the point where the oxygen-containing gas meets the fuel local temperatures up to about 1700xc2x0 C. occur. Coaxial to the first cooling chamber a common second cooling chamber is expediently provided, which is surrounded by the first cooling chamber. It may be recommended to provide a connecting passage for cooling liquid between the first and the second cooling chamber.
A further development of the burner consists in that inside the area of the first cooling chamber at least one passage for an insertable and removable auxiliary burner is provided. This auxiliary burner may be used for instance only in the start-up phase of the gasification operation, and it is removed from the burner assembly during the continuous operation.
As liquid, carbonaceous fuel there may for instance be used heavy oil, a pumpable slurry of granular coal or petroleum coke in water or in liquid hydrocarbons, as well as an emulsion of bitumen or asphalt in water. As O2-containing gas there is normally used technically pure oxygen or oxygen-enriched air, if the nitrogen content is not disturbing.